The embodiments described herein relate generally to an injector, and more particularly to a medicament delivery device for mixing a medicament and delivering the medicament into a body of a patient.
Exposure to certain substances, such as, for example, peanuts, shellfish, bee venom, certain drugs, toxins, and the like, can cause allergic reactions in some individuals. Such allergic reactions can, at times, lead to anaphylactic shock, which can cause a sharp drop in blood pressure, hives, and/or severe airway constriction. Accordingly, responding rapidly to mitigate the effects from such exposures can prevent injury and/or death. For example, in certain situations, an injection of epinephrine (i.e., adrenaline) can provide substantial and/or complete relief from the allergic reaction. In other situations, for example, an injection of an antidote to a toxin can greatly reduce and/or eliminate the harm potentially caused by the exposure. Similarly, an injection of glucagon can reduce and/or eliminate the harm potentially caused by reduced blood glucose levels in individuals who suffer from hypoglycemia.
Because emergency medical facilities are not always available when an individual is suffering from a medical condition, some individuals carry an auto-injector to rapidly self-administer a medicament in response to such medical conditions. Some known auto-injectors include a vial containing a liquid medicament and a spring loaded needle to automatically penetrate the user's skin and inject the medicament. The storage of certain medicaments in a liquid form, however, can result in a shorter shelf life and/or an unstable medicament. Accordingly, some known auto-injectors include a vial containing a first medicament that is separated from a second medicament. Such auto-injectors are often referred to as “wet/dry” auto-injectors, because one medicament is often a liquid (e.g., water or another diluent) and the other medicament can be substantially solid or dry (e.g., glucagon powder). In use, the first medicament and the second medicament must be mixed prior to injection.
Some known wet/dry injectors, however, require that the user manually actuate a mixing mechanism prior to injection (e.g., by twisting a portion of the device to complete the mixing step). Such configurations can, however, result in incomplete mixing and/or an injection occurring without mixing. In addition, the operation of some known wet/dry delivery systems includes manually inserting the needle into the skin prior to activation and subsequent medicament delivery. The operation of such configurations may also include separately attaching a needle to prepare the device for injection, resulting in a delay in delivery of the medicament. Moreover, such configurations can be complicated, making them difficult for a user to operate during an emergency situation or by an individual without medical training.
Some known wet/dry injectors employ a single mechanism to automatically mix and inject the medicaments contained therein. Because the mixing operation is not independent from the injection operation in such configurations, however, the medicament can be injected prior to the completion of the mixing operation and/or prior to the injector being properly positioned for the injection operation.
Some known wet/dry injectors are configured such that a user can manually vent and/or purge a portion of air included in the medicament container (e.g., mixed with or a part of the glucagon powder). In some embodiments, such known injectors are generally oriented in a predetermined manner (e.g., with the needle end facing upward) to facilitate the venting process. Therefore, the venting process can be performed incorrectly or incompletely.
Thus, a need exists for an improved auto-injector that can separately store two or more medicaments and that can vent, mix and inject the medicaments in distinct operations. A need also exists for improved methods of filling medicament containers used in such devices.